This paper examines the empirical evidence of a theoretical economic model of the effect of labor organization on IPM adoption developed by Beckmann and Wes seler (2003). We use cross section data collected from the participatory farming system survey of 150 durian growers in Chanthaburi, Thailand, on March  April 2005. In contrast to many studies of IPM adoption, this work uses the form of farm labor organiza tion as endogenous factor for identifying the rate of IPM adoption of durian growers. Instrumental variables method was employed to relate econometrically a set of suspected variables as instruments of labor organization to the rate of IPM adoption of duri an growers. Results show that, among others, farms employing hired labor have a lower adoption rate of IPM, which supports the theoretical model.